C m3/F#
The C m3 chord consists of the C (Perfect unison) and D# (Minor third) notes, with F# as the bass note.

How to play the C m3/F# chord
- Play F# as the lowest bass note in the left hand
- Find C (Root) on the piano keyboard
- Add D# (Minor third) — 3 semitones above C
- Press all 3 notes simultaneously to sound the C m3/F# chord